A Si MOSFET based High-Power Wireless EV Charger with Wide ZVS Operating Range

This article proposes a new digitized modulation scheme suitable for a high-power wireless electric vehicle charger employing an integrated boost multilevel converter (IBMC) as its primary-side converter. Using the proposed modulation scheme, an IBMC can generate a boosted square-wave-shaped ac voltage with a controllable amplitude, enabling it to regulate the power efficiently over a wide load and/or coupling range while achieving zero voltage switching for all switches. This article focuses on the steady-state operating principles of the proposed digitized modulation scheme. Key practical considerations, such as capacitor voltage balancing and semiconductor device selection, are highlighted. To verify the benefits of the proposed modulation scheme, an SAE J2954 WPT2/Z2 compliant wireless EV charger prototype that uses an IBMC as the primary converter is designed and built. 200 V Si MOSFETs are employed in the 12 submodules (SMs) that compose the IBMC. The secondary side employs a passive rectifier, and the power flow is controlled using only the IBMC. This system maintains an efficiency between 90% and 93% when regulating power transfer at 7.7 kW under a 220% variation in coupling factor (i.e., 0.14–0.31) and a 150% variation in battery voltage (i.e., 280–420 V).